Sheet-like waterproofing membrane laminates are well-known for application to concrete and other substrates. These laminates typically comprise a carrier sheet and a pressure sensitive adhesive layer (and optionally other layers). In many applications, the waterproofing sheet material is applied to a concrete substrate that has already been formed, such as a building foundation. In such a case, the adhesive layer of the membrane is applied against the cured concrete surface. In another technique, the waterproofing membrane is affixed to a lagging with the carrier sheet against the lagging and the adhesive portion (which may have an optional coating thereon) facing toward the cavity, circumscribed by a concrete form, in which the concrete is poured. The adhesive portion of the membrane will adhere to the freshly poured concrete (i.e., post-cast concrete), thus providing a fully adhered waterproofing membrane on the cured concrete surface after the form is removed. This technique is sometimes referred to as “blind side” (or pre-applied) waterproofing. A similar process may be used on horizontal surfaces where the membrane is applied to compacted soil or gravel or to a concrete slab, with the adhesive portion facing upward, then casting concrete against the membrane.
In addition to the carrier sheet and pressure sensitive adhesive layer, typical commercial waterproofing membranes include a removable release sheet that is used to prevent the adhesive portion of the membrane from adhering to the carrier sheet or other portion of the membrane when the membrane is rolled up. This release sheet must be removed from the membrane prior to or during installation and disposed in the trash, thus creating environmental waste.
U.S. Pat. No. 3,900,102 (Hurst) discloses one such membrane comprising a polyethylene support sheet, a bituminous adhesive and a releasable siliconized paper for protecting the adhesive. The release paper is removed as the membrane is unrolled and adhered to a building substrate (see Hurst FIG. 4). U.S. Pat. No. 4,751,122 (May) discloses a membrane laminate that includes a sheet-like paper substrate with a release coating (e.g., silicone) on one face and a waterproofing pressure sensitive adhesive on the other face. This membrane also includes a removable strip along the edge which, when removed, permits overlapping seams to adhere. U.S. Pat. No. 4,172,830 (Rosenberg) and U.S. Pat. No. 4,215,160 (Rosenberg) disclose paperless membrane laminates that include a silicone release coating on the outer surface of the carrier sheet to prevent the adhesive layer from adhering to the carrier sheet when the membrane is rolled up. U.S. Pat. No. 5,254,661 (Wilson) discloses a similar type of paperless membrane laminate in which the release coating is a water-based silicone emulsion. During installation, edge portions of the release coating may be removed by wet abrasion to permit adhesion of overlap seams of adjacent membranes.
U.S. Pat. No. 4,994,328 (Cogliano) discloses a waterproofing membrane capable of adhering to freshly poured concrete (i.e., blind-side or pre-applied waterproofing). The membrane has a bituminous adhesive layer that is coated with a non-tacky, water-insoluble polymeric coating such as, for example, a polyvinyl alcohol, silica, and glycerin mixture in a weight ratio of 1:10:0.5. The coating purportedly protects the adhesive layer while permitting a strong adhesive bond to freshly poured concrete. However, the coating can be slippery when wet and, thus, not suitable for foot traffic. U.S. Pat. No. 5,316,848 (Bartlett) discloses a similar blind-side waterproofing membrane that includes a carrier layer, a pressure sensitive adhesive layer, and a protective coating on the adhesive layer, wherein the protective coating may be selected from various types of polymers, preferably an acrylic-based elastomer, such as styrene butyl acrylate. U.S. Pat. No. 5,496,615 (Bartlett) discloses a similar membrane laminate where the protective coating has a finely divided particulate material, such as sand, calcium carbonate, cement, titanium dioxide, etc., dusted thereon. The particulate material may have a particle size in the range of 0.1 to 1000 μm, preferably 0.2 to 100 μm. It should be noted that the particulate material is dusted onto the protective coating layer, not the adhesive layer.
U.S. Pat. No. 5,271,781 (Anno) discloses a waterproof sheet for concrete structures. The sheet is made of a thermoplastic synthetic resin and has cement powder pressed against and adhered to a surface of the sheet. However, the waterproof sheet does not include a pressure sensitive adhesive. In use, a cement paste layer is applied to the surface of a concrete substrate, then the powder coated sheet is applied against the wet cement paste layer, whereby the sheet adheres to the cement paste layer. U.S. Pat. No. 5,543,188 (Te'eni) discloses a waterproofing membrane that includes a polymeric sheet having fibrous surface layers on opposite faces. The fibrous surface layers are impregnated with a cementitious bonding material (e.g., cement powder) that is in a substantially non-hydrated condition, which will bond to wet concrete cast against the membrane. This membrane does not include a pressure sensitive adhesive.
U.S. Pat. No. 6,500,520 (Wiercinski) discloses a membrane laminate having a carrier support sheet, an adhesive layer, and embedded on the adhesive layer a layer of granulated inorganic particulates capable of reacting with concrete, such as aluminum oxide trihydrate, silica dioxide, fly ash, blast furnace slag, alkali or alkaline earth metal salts, etc. The particles, which may range in size from 5 to 1000 μm, may optionally be attached to the adhesive layer using a water-soluble material such as ethylene vinyl acetate or polyvinyl alcohol.
WO2005/091931 (Seth) discloses a shaped waterproofing membrane having a three-dimensional contour that may be used to cover detail areas such as tiebacks. These shaped membranes may include a protective layer such as particles embedded into the outer adhesive layer and/or outer polymer coating layer. The particles may be the same particles described in the aforementioned Bartlett and Wiercinski patents.
U.S. Pat. No. 6,746,764 (Anspach) discloses self-adhering surface coverings such as floor tiles. The surface coverings include a substrate, such as tile, parquet, etc., having a pressure sensitive adhesive layer and a barrier layer disposed on the adhesive layer. The barrier layer permits the surface coverings to be stacked without the need for a release layer between adjacent surface coverings. The barrier layer includes particles that are crushable above 20 psi and that have a diameter at least equal to or greater than the thickness of the adhesive layer (typically about 2-6 mils (50-152 μm)). The particles may be uniformly distributed on the adhesive layer and may cover about 1% to 10% of the adhesive surface. While the particles may include a variety of materials, there is no suggestion to use cement or hydrated cement. Since this disclosure is directed to surface coverings such as floor tiles, there is no suggestion to cast concrete against the barrier layer.
Typical commercial waterproofing membranes used for blind-side (or pre-applied) applications include a release sheet and unroll wrong side up with the adhesive portion (or protective coating portion) facing downward. This forces the installer to first unroll then flip over a large, unwieldy membrane prior to installing it. Alternatively, two installers are needed to lift the heavy roll so that it may be unrolled from the top.
It would be advantageous to provide a waterproofing membrane that binds strongly to concrete cast against its surface, particularly after the membrane has been exposed to sunlight. In addition, it would be advantageous to provide a waterproofing membrane that has a highly reflective surface that will protect the adhesive layer from sunlight. Further, it would be advantageous to provide a waterproofing membrane that has an outer surface that will tolerate foot traffic. It would also be advantageous to provide a waterproofing membrane that does not require a release sheet that must be removed and disposed of at the job site.